There has been proposed an information input output method for reading a bar code printed on a printed material and outputting voice or audio information. For example, a method has been proposed to store information corresponding to a given key information in a storage means, retrieve the information corresponding to the key read by a bar code reader, and output information and the like. In addition, in order to output many kinds of information and programs, a technique has been proposed to generate a dot pattern in which fine dots are arranged based on a predetermined rule, use a camera to scan the dot pattern printed on a printed material as image data, and digitize the data to output audio information.
However, the aforementioned conventional method of using a bar code to output audio information and the like has a problem in that a bar code printed on a printed material may obstruct the view. There is another problem in that, since a bar code is large enough to occupy a part of the paper, it is substantially impossible to arrange many bar codes in a limited layout space with each bar code disposed in part of text or a sentence or for each meaningful character and other object appearing in an image such as a photograph, a picture, and a graphic so as to be easily viewed.
In this context, much attention has been paid on a technique for reading a code or a coordinate using a fine dot pattern which can be superimposed on a medium surface (printed surface) as the inventors have proposed.
According to this kind of dot pattern, a dot pattern defined for each block in a predetermined area is read by an optical reading means and is converted into a predetermined code or coordinate. Then, the corresponding character, voice, image, and animation information is outputted.
However, it is necessary to determine the number of blocks (fixed length) containing the dot pattern therein. Accordingly, when a fixed length block is used, the amount of data to be defined is limited due to its fixed length, or there is a possibility that the printed area is occupied by a block having no meaning since the data is small and need not use all the fixed length blocks.
The present invention has been invented to solve the above mentioned problems. Thus, an object of the present invention is to provide a dot pattern technique with flexible length of data to be registered and with enhanced security by arranging a dot pattern to be disposed on a printed material, especially a block containing the dot pattern, on the basis of a new rule.